A. Field of the Invention
The invention relates generally to drive systems for a tracked vehicles, such as an armored tank. More specifically, the invention is directed to an electro-mechanical drive system for a full-track vehicle, the drive system including both electric motors and gearing means for mechanically transferring power from one to the other side of the vehicle, for the propulsion and steering of the track-drive wheels of the full-track vehicle.
B. Description of the Related Art
German publication DE-PS 21 14 951 describes a presently known purely mechanical drive system for a fulltrack vehicle, such as a tank. The known drive system includes a drive motor, at least one steering control unit, a differential gear arrangement, a drive control connection between the drive motor and a drive control element of the differential gear arrangement, a steering control connection between the steering control unit and a steering control element of the differential gear arrangement, and two control outputs of the differential gear arrangement for driving track-driving wheels of the full-track vehicle.
The driving motor is normally a diesel motor. From it a drive control connection containing a gear shift goes to drive control elements of two differential gear sets in the form of two planetary gears. Further, from the drive motor a steering control connection containing a steering control unit goes to steering control elements of the two differential gears. Instead of the mechanical steering control unit, hydraulic steering control units are also known. In addition, diesel-electric drive systems are known as well. In these diesel-electric drive systems, each track-driving wheel has its own electric motor with a reduction gear. The current for these electric motors is generated by a generator which is driven by a diesel engine. When the tracked vehicle runs through curves, the outer track requires much more power than the inner track. In the known diesel-electric drive system this has the disadvantage that the wattless output occurring in curves must be transmitted electrically in the form of a power transfer from the inner track to the outer track. This requires higher-rated electric motors going beyond the maximum required drive power on each side of the vehicle and results in increased cost of control and regulating equipment of the drive system.
Furthermore, the speeds and torques of the track-driving wheels must be regulated as a function of the particular position of the accelerator pedal or gas pedal, and also of the steering wheel under continually changing external influences. Such external influences are, in particular, the continually changing nature of the ground on which the tracked vehicle runs, as well as the frequent movements of the steering wheel of the tracked vehicle.